Overweight children often eat more healthily than their thinner classmates,
according to research suggesting that a lack of exercise, rather than a junk
food diet, may be to blame for obesity.

A study of 900 primary school pupils in Norway found that fat children ate healthy foods - such as fruit, vegetables, fish, and brown bread, as well as low-calorie cheese and yoghurt - more frequently than their normal-weight peers.

The research suggested that a good diet without exercise may not be enough to prevent weight gain.

The findings, in a study by Telemark University College and the Norwegian Institute of Public Health, represent the latest contribution to the debate over whether diet or exercise is more important in combating obesity.

It follows research published in September that suggested that diet had the greatest influence on weight.

Academics monitored the weight, exercise levels and eating habits of 924 children aged nine and 10 and questioned their parents about their own lifestyles. The children were asked how often they had eaten a variety of foods, both for main meals and snacks.

The study found that fat children drank juice more often than their classmates of normal weight, who regularly consumed fizzy drinks and ate processed foods such as burgers, sausages, biscuits, pizza and sweets.

The researchers suggested families with children who are overweight may be more aware of the food they choose to eat than those who are less concerned about putting on extra pounds.

Professor Anne Lise Brantsæter, from the NIPH, said: “It is positive that parents and children emphasise healthy food choices.

“However, it is important to note that the amount of healthy foods must be adapted to a child's activity level to limit further weight gain.

“Obesity is a growing problem that can have unfortunate consequences for the children both physically and mentally.”

The researchers also found that overweight children were more likely to have overweight parents.

Prof Brantsæter said: “There are many contributing factors to obesity and it is important that both parents and children are given good guidance and support early on.”

A previous study, from Professor John Speakman at the University of Aberdeen, came to a different conclusion, blaming excessive food intake for rising obesity levels.

He found that overall physical activity levels have remained constant for the last quarter of a century while weight levels have soared.

His research, published in September, found that on average men burned 1,380 calories per day in the 1980s, the same as today, while women used 950 calories. The major change has been in calorie intake, which has increased by at least a third to 3,500 calories a day, he said.